As expected, Yahoo this morning announced its acquisition of blogging phenomenon Tumblr. The Internet giant has bought the six-year old New York company for “approximately $1.1 billion”, substantially all of which will be paid in cash.

That’s the gist of the news, folks, although here are some interesting stats and figures from the press release while you make up your mind whether this is a brilliant or idiotic move, or somewhere in between.

With more than 300 million monthly unique visitors and 120,000 signups every day, Tumblr is one of the fastest-growing media networks in the world. Tumblr sees 900 posts per second (!) and 24 billion minutes spent on site each month.

On mobile, more than half of Tumblr’s users are using the mobile app and do an average of 7 sessions per day. Its tremendous popularity and engagement among creators, curators and audiences of all ages brings a significant new community of users to the Yahoo! network.

The combination of Tumblr+Yahoo! is expected to grow Yahoo!’s audience by 50 percent to more than a billion monthly visitors, and to grow traffic by approximately 20 percent.

The deal offers unique opportunities for both companies. Tumblr can deploy Yahoo!’s personalization technology and search infrastructure to help its users discover creators, bloggers, and content they’ll love.